The concept of frailty relates to the ability to cope with acute stressors being limited and susceptibility to decline having a relationship to intrinsic “reserve.” Frailty is a distinct clinical syndrome from age and multimorbidity [1]. Frailty has emerged as a crucial clinical risk factor for stroke and has independent associations with poorer clinical outcomes. There is a strong desire with an ageing population to quantify the burden of frailty amongst populations with cerebrovascular disease. This will require a greater understanding as to the most pragmatic assessment tools and optimisation of procedures linked to utilization in acute, sub-acute, and rehabilitation settings [1].
In preparing this collection, the amalgamation offered a unique opportunity to advance the science and expertise in this field, through cross-speciality collaborations designed to address challenging issues at the forefront of frailty research. The collection broadly includes themes involving epidemiology of frailty in different stroke settings, prognostic implications of frailty in stroke and TIA populations, and assessment of frailty using novel approaches.
At the outset, Binning et al. [2] provided an important contribution to the literature, addressing cognitive frailty, cognitive reserve, and brain frailty. This systematic review highlighted the presence of methodological heterogeneity, but confirmed brain frailty is the most common form of frailty with a clear association with poorer outcomes [2].
Although the vast majority of literature focusses on post-stroke frailty, Munthe-Kaas et al. [3] provide data on the predictive value of pre-stroke frailty on longer term outcomes. An older cohort (mean age 72.8 years), followed up for 3 years, demonstrated the importance of frailty indices over premorbid mRS in prognostication [3].
Lewis et al. [4] provide data on whether frailty is independently associated with 28-day mortality following acute intracerebral haemorrhage. This association is confirmed and provides further evidence supporting the value of frailty evaluation to support immediate decision-making and prognostication [4].
Frailty is considered a “stressor” [1] and current assessment tools do not incorporate serum-based characteristics. In those undergoing mechanical thrombectomy, this blood-based frailty index (18 blood parameters of which 9 were used in the tool) was able to identify frailty in those undergoing the procedure [5].
The frailty research landscape has predominantly focused on inpatient assessment of moderate/severe stroke populations and there is a paucity of data in ambulatory minor stroke populations. Elliot et al. [6] identified the prevalence of frailty in this setting and strengthen the case for routine assessment in settings beyond acute inpatient services.
Sarcopenia, an age-related muscle loss syndrome, has associations with frailty, though challenges remain around assessment, particularly in an acute stroke setting. Knight et al. [7] used computed tomography neck imaging to assess the feasibility of sarcopenic assessment in this population. Further studies are needed in larger cohorts, though pragmatic review of routine angiograms for this marker seems novel and feasible [7].
Cross-speciality data addressing stroke complication were represented in the collection. An example of this is a scoping review – targeting the current practice around screening for osteoporosis in post-stroke populations [8]. An important finding of this review is the lack of any post-stroke osteoporosis screening guidelines [8]. There is an urgent unmet need given recent data on the prevalence of serious falls after stroke [9].
Lastly, collateralisation can improve stroke prognosis, though the lack of collateral flow has not previously been associated with adverse phenotypes. Arsava et al. [10] show diminished physiological reserve associates with impaired collateral flow and could be used as part of frailty phenotyping. Furthermore, it elucidates the possible mechanisms through which frailty may affect stroke. This study uniquely brings together radiological and systemic factors and considers the interplay between the two.
In summary, the collection has attracted a breath of research, creating a disruptive step change in our understanding and generating avenues for future research. The studies in this collection, and across the stroke frailty field, have tended to be observational and single centre. However, a key direction identified in the aforementioned literature relates to the benefits of using advanced imaging alongside clinical frailty assessment, and trials should embed this approach. The importance of frailty is now clear, and we need future research to investigate embedding frailty in interventional trials (preferably multi-centre), frailty to design, develop and optimise stroke services and care pathways, and exploring fundamental mechanisms underpinning the effects of frailty in stroke.
Acknowledgments
The authors would like to thank Dr. Oliver Todd for his contribution to peer review of manuscript(s) within the collection.
Conflict of Interest Statement
Several of the manuscripts included in the collection. Dr. Jatinder Minhas was a member of the Journal’s Editorial Board at the time of submission.
Funding Sources
No funding was received for this paper.
Author Contributions
J.S.M., T.J.Q., N.R.E., and L.C.B. orchestrated the collection and prepared this manuscript jointly.
